testing regulator on 76 gl1000

[luigipasto]

I'd like to test the regulator on my bike. The shop manual states that the regulator should divert current to ground through the green wire (as measured by an ammeter) when the battery voltage reaches between 14 and 15. I'm not sure how much current though. The ammeter suggested is for measuring 0-5 amps. Nowhere does it say how many amps? I'm not an expert and may be missing something very simple. Any ideas/lessons welcome...

[cfairweather]

Have you seen this document?
https://www.randakksblog.com/comprehens ... eshooting/

[luigipasto]

Thanks Cedric! This was very helpful however it's still not clear to a non-expert like me. I guess it's more important that the voltage not exceed about 15 than knowing the exact current to expect from the regulator. If the voltage climbs above 15 then the regulator is not working.....

[cfairweather]

There are others that may provide more information but I would just do the basic tests and not worry about the current. As long as the devices pass the tests that are listed in that document, you will be fine. I have found the electronic devices pretty reliable on the GL1000 except for the Reserve Lighting Unit and the 7 volt regulator. I typically remove the RLU per Chilton's manual and I replace the 7 volt regulator with a homemade unit. I think removing the RLU must take a big load off the entire electrical system. If you need a regulator, I will give you one as I have several. Just pay the shipping.

[pidjones]

Current diverted to ground by the regulator is going to be dependent on how much is generated by the alternator (which is dependent on engine RPM to some extent) and how much is used by various loads (ignition, lighting, auxiliary devices). So, that really would be very hard to specify. And, regulators can and do fail. The regulator on my '79 failed and allowed voltage to go over 17 volts, which fried some electronics that I was testing. Easily solved by replacing the regulator and rectifier with a new reg/rect combo unit. After that, I replaced the slow voltmeter in the dash with a digital. When the '75 that I have waiting for rescue next year hits the road, it will also have a digital voltmeter.

[Sidecar Bob]

Testing the regulator is simple. Disconnect the headlight, connect a voltmeter across the battery, start the engine and increase the RPM to between 3,000 and 4,000.
If the battery voltage is between 14 and 15V the regulator is working as it should.
If the voltage is below 14V or above 15V you have a problem but don't assume it is caused by the regulator until you have checked every connection between the alternator and the battery.
BTW: Don't just look at the connections and feel if the wires move, with the key off undo and redo all of the connections
NOTE: Disconnect the battery's negative cable and make sure it can't touch the battery terminal while working on the positive cable's connections. Failure to do so can cause bad burns to your hands and even lead to the battery exploding.

[luigipasto]

Thanks to all. As usual, this is very instructive and helpful. Thanks for the offer cfairweather, I'll do all the testing as instructed before concluding the regulator is bad.